1. Field of the Invention
This invention relates to an image storing method for storing image signals in a storage device. This invention also relates to an image output system for reproducing images in a medical network system, or the like, in which the image storing method is employed.
2. Description of the Prior Art
Various image forming apparatuses (modalities) for diagnosis, in which X-rays, or the like, are utilized, have heretofore been used in the medical field. As such modalities, computed radiography (CR) apparatuses, computed tomography (CT) scanners, magnetic resonance imaging (MRI) apparatuses, and the like, have been used in practice. An image having been formed by each modality is displayed on a cathode ray tube (CRT) display device or is reproduced on film by a laser printer (LP), or the like. The reproduced image is utilized for making a diagnosis, e.g. for investigating the presence or absence of a diseased part or an injury or for ascertaining the characteristics of the diseased part or the injury.
The CR apparatuses are radiation image recording and read-out apparatuses. With the radiation image recording and read-out apparatuses, a radiation image of an object, such as a human body, is recorded on a sheet provided with a layer of a stimulable phosphor (hereinafter referred to as a stimulable phosphor sheet). The stimulable phosphor sheet, on which the radiation image has been stored, is then exposed to stimulating rays, such as a laser beam, which cause it to emit light in proportion to the amount of energy stored thereon during its exposure to the radiation. The light emitted by the stimulable phosphor sheet, upon stimulation thereof, is photoelectrically detected and converted into an electric image signal. Recently, the CR apparatuses are widely used in practice.
With the rapid advances made in communication technology and computer technology in recent years, medical network systems (hereinbelow referred to simply as the xe2x80x9cnetworksxe2x80x9d) utilizing computers have been built in hospitals. The aforesaid modalities, which were used in the past as stand-alone apparatuses, constitute part of the network as image information input apparatuses. Also, CRT display devices and LP""s constitute part of the network as image output devices. Typical examples of the image output devices, which are to be connected to the network, include various kinds of soft copy terminals having image output quality according to the purposes for which the images are used, such as diagnosis terminals provided with CRT display devices having resolution of 2,000 TV lines, low-cost diagnosis terminals provided with CRT display devices having resolution of 1,000 TV lines, reference terminals having output quality lower than the output quality of the low-cost diagnosis terminals, and retrieval terminals for the above-enumerated terminals. Besides the soft copy terminals, hard copy devices, such as LP""s, are often connected to the network.
Ordinarily, besides the image input apparatuses and the image output devices described above, the network is also provided with a storage device for storing pieces of image information, which are received from the image input apparatuses, in the form of the original image signals or signals, which have been compressed in a predetermined format, on optical disks, or the like. In accordance with the purposes for which the images are used, various kinds of the image output devices read the image signals from the storage device, carry out predetermined image processing on the image signals, and reproduce visible images from the processed image signals.
As described above, with the conventional displaying technique, pieces of image information are stored in the form of the original image signals (or the compressed image signals). Also, in every case where an image is to be displayed on one of the terminals, the corresponding original image signal (or the corresponding compressed image signal) is read from the storage device, predetermined image processing is carried out on the image signal by each terminal, and a visible image is reproduced from the processed image signal and displayed on the terminal. However, with the conventional displaying technique, for example, in both the cases wherein a medium resolution image for diagnosis is to be displayed on a low-cost diagnosis terminal provided with a CRT display device having resolution of 1,000 TV lines, and the cases wherein a retrieval image is to be displayed on a retrieval terminal, when the image signal is read from the storage device into the low-cost diagnosis terminal and the retrieval terminal, the same length of time as that required for the diagnosis terminal provided with a CRT display device having resolution of 2,000 TV lines to read the image signal for the displaying of a high resolution image is required at the low-cost diagnosis terminal and the retrieval terminal. Also, it is necessary for the low-cost diagnosis terminal to carry out predetermined image processing for the low-cost diagnosis terminal on the received image signal, and it is necessary for the retrieval terminal to carry out predetermined image processing for the reference terminal on the received image signal. However, long time is required to carry out the image processing. Therefore, at both the low-cost diagnosis terminal and the retrieval terminal, considerable time is required for a visible image to be displayed ultimately. In particular, as for the image output devices, such as the retrieval terminals, on which it is sufficient for a visible image having comparatively bad image quality to be displayed, the problems have heretofore been occurred in that unnecessarily long time is taken before the visible image is displayed.
Further, recently, image output systems, in which an internet Web browser using, for example, Internet Imaging Protocol (IIP) known in the field of personal computer networks, or the like, have heretofore been constructed. With the image output systems, image signals are stored in a Web server, an image signal is read from the Web server into an image display device, which is located at a remote site, and a visible image is reproduced from the received image signal and displayed on the image display device. In such cases, only one kind of image signals for high resolution images are stored in the Web server. Therefore, the problems occur in that, in cases where a high resolution image need not be displayed and it is sufficient for an image having comparatively bad image quality to be displayed, long time is required for the image to be displayed.
The primary object of the present invention is to provide an image storing method for storing image signals in a storage device such that, for example, in a network comprising a plurality of image output devices having different levels of image displaying quality according to purposes for which the displayed images are used, the image signals having been read from the storage device may be quickly transferred or outputted (displayed) according to purposes for which the displayed images are used.
Another object of the present invention is to provide an image output system, in which the image storing method is employed.
The present invention provides an image storing method for storing image signals, which represent images, in a storage device, wherein a plurality of image signals, which represent a single image and have been subjected to different processes with respect to at least both of resolution altering processing and image processing, are stored in the storage device.
As the storage device, one of storage devices for storing image signals on various kinds of storage media, such as optical disks, or one of various servers, such as Web servers known in the field of personal computer networks, may be employed.
The term xe2x80x9cresolution altering processingxe2x80x9d as used herein means the signal processing for lowering or enhancing the resolution. For example, the resolution altering processing may be the signal processing for lowering the resolution, such as xc2xc reduction or thumbnail {fraction (1/16)} reduction, or the signal processing for enhancing the resolution. The term xe2x80x9cimage processingxe2x80x9d as used herein means the processing for altering the details of the image themselves, such as gradation processing, emphasis processing, or frequency processing. The term xe2x80x9cimage processingxe2x80x9d does not embrace the processing for altering the form of the image, such as resolution altering processing, bit number altering processing for altering the number of bits of the signal, and compression processing for compressing the amount of the signal.
In the image storing method in accordance with the present invention, a plurality of image signals, which represent a single image and have been subjected to different processes with respect to at least both of the resolution altering processing and the image processing, are stored in the storage device. For example, in cases where two image signals are stored as the plurality of the image signals, the two image signals may be the ones, which have been subjected to different processes with respect to the resolution altering processing, such that the levels of the resolution of the two image signals may become different from each other, or such that the resolution of one of the two image signals may be kept the same as the resolution of the original image signal and the processing for altering the resolution may be carried out on only the other image signal, and which have been subjected to different processes with respect to the image processing, such that different kinds of image processing may be carried out on the two image signals, such that image processings of the same kind but with different processing characteristics may be carried out on the two image signals, or such that one of the two image signals may be kept the same as the original image signal and image processing may be carried out on only the other image signal. Therefore, for example, one of the image signals may be the original image signal, which has not been subjected to any processing with respect to the resolution and the image processing, and the other image signal may be the one, which has been subjected to the resolution altering processing and the image processing. Also, in cases where three or more image signals are stored as the plurality of the image signals, all of the image signals need not necessarily have the relationship described above, and at least two image signals among the plurality of the image signals may have the relationship described above. Besides the resolution altering processing and the image processing, the image signals may have even further been subjected to various other processings, such as the bit number altering processing and the compression processing.
The present invention also provides an image output system, comprising:
i) a storage device for storing image signals, and
ii) a plurality of image output devices for reading the image signals from the storage device and reproducing images from the thus read image signals, the image output devices having different levels of output image quality,
wherein a plurality of image signals, which represent a single image and have been subjected to different processes with respect to at least both of resolution altering processing and image processing, are stored in the storage device, each of the different processes corresponding to one of the image output devices, and
each of the image output devices reads an image signal, which corresponds to the image output device, from the storage device and reproduces an image from the thus read image signal.
The image output system in accordance with the present invention is also applicable when the plurality of the image signals, which are to be stored in the storage device, have not been prepared previously. In such cases, the image output system should preferably be modified such that it may be provided with a processing unit for obtaining the plurality of the image signals, and the storage device may store the plurality of the image signals, which have been obtained from the processing unit.
The term xe2x80x9ca plurality of image output devices having different levels of output image qualityxe2x80x9d as used herein means the image output devices having different levels of output quality in accordance with the purposes for which the images are used (in accordance with whether the output images are the images for diagnosis, the images for retrieval, or the like). For example, the image output devices may include various kinds of soft copy terminals having different levels of resolution, such as accurate diagnosis terminals, which are provided with CRT display devices having resolution of 2,000 TV lines and which can display high resolution images, low-cost diagnosis terminals for ordinary diagnosis, which are provided with CRT display devices having resolution of 1,000 TV lines and which can display medium resolution images, reference terminals having output quality lower than the output quality of the low-cost diagnosis terminals, and retrieval terminals for the above-enumerated terminals. Besides the soft copy terminals, hard copy devices, such as LP""s, may be included in the image output devices. An image output device, which is capable of displaying a high resolution image, can also display a low resolution image. In such cases, a single image output device, which is capable of displaying a high resolution image, is equivalent to a plurality of image output devices and is therefore regarded as a plurality of image output devices. Also, the hard copy terminals described above have different levels of output quality with respect to the resolution. However, the hard copy terminals are not limited to such hard copy terminals and may have different levels of output quality with respect to other characteristics, such as contrast characteristics, in accordance with the purposes for which the images are used. This also applies to the soft copy terminals.
The term xe2x80x9ca plurality of image signals having been subjected to different processes corresponding to image output devicesxe2x80x9d as used herein means the plurality of the image signals, which have been subjected to processes conforming to the output quality of the image output devices. For example, as one of the image signals, the original image signal, which has not been subjected to any processing with respect to the resolution and the image processing, may be assigned to an accurate diagnosis terminal, which is provided with a CRT display device having resolution of 2,000 TV lines and which can display a high resolution image. Also, an image signal, which has been subjected to the resolution altering processing for xc2xd reduction and the image processing with predetermined characteristics, may be assigned to a reference terminal.
With the image storing method and the image output system in accordance with the present invention, the plurality of the image signals, which represent a single image and have been subjected to different processes with respect to at least both of the resolution altering processing and the image processing, are stored in the storage device. Therefore, when each of the image output devices reads an image signal from the storage device and reproduces an image from the read image signal, the image output device can read a desired image signal from the plurality of the stored image signals and in accordance with the output quality (the difference in display resolution, whether the image processing is or is not necessary, or the like) of the image output device. Accordingly, as for the image output device other than the image output device for reproducing an image having good image quality by using the original image signal, the desired processed image signal may be read from the storage device into the image output device, and it is not necessary for the image output device to carry out the image processing. As a result, the image output device can reproduce the image more quickly than when the image output device reads the original image signal from the storage device, carries out the predetermined image processing on the original image signal, and then reproduces the image. Also, instead of the original image signal being read from the storage device, the image output device can read the image signal, which has been obtained by reducing the resolution and is composed of an amount of signal smaller than that of the original image signal, from the image output device. Therefore, the signal transfer speed can be kept high, and the time required for the image to be outputted can thereby be kept short.